Detecting fluid levels is important for a variety of reasons. Marine and aviation applications require accurate measurements of fuel to ensure sufficient supplies to reach intended destinations. Aviation applications are exceptionally important to monitor the fuel levels in multiple tanks to ensure proper balance of levels to impart the least impact on a plane's aerodynamics, which can be significantly affected by changes in a plane's three-dimensional center of gravity.
Another important measurement function is to ascertain the presence of, and amount of, any contaminants in fuel to ensure the safe and proper operation of engines operated with the fuel. Entry of contaminants into an operating engine can lead to severe performance problems and even engine failure. A means to constantly monitor the presence and amount of contaminants, particularly water, is an essential component of any fuel measurement system.
An accurate, reliable and safe method of measuring the amount of liquid in a container is essential. Applications include fuel tanks containing volatile liquids, although the invention described herein can accommodate a wide range of liquids, regardless of their volatility characteristics. Other parameters that must be ascertained with accuracy and consistency are the type of fuel and the contamination content, if any. A further consideration is a need for hardware that meets the EMI, ESD and Interface requirements of a container, such as an aviation fuel tank, in its environment in a safe manner.
Prior radar technology includes methods to scan, lock on and track targets. The basic approach is to transmit a signal that scans targets, perform gating on a receiver and select targets to lock onto and track. Analysis of the received signal can then be used to determine the distance (range) of the target and to perform signature recognition to define the type of target and its characteristics. Combining radar technology with transmission line theory through a shielded cable solves the problems attendant with sensing liquid levels in containers, particularly those used in the aviation field.